Efficient purification of His-tagged protein by superparamagnetic Fe3O4/Au-ANTA-Co2+ nanoparticles

Superparamagnetic Fe3O4/Au nanoparticles were synthesized and surface modified with mercaptopropionic acid (MPA), followed by conjugating N alpha,N alpha-Bis(carboxymethyl)-L-lysine hydrate (ANTA) and subsequently chelating Co2+. The resulting Fe3O4/Au-ANTA-Co2+ nanoparticles have an average size of 210 nm in aqueous solution, and a magnetization of 36 emu/g, endowing the magnetic nanoparticles with excellent magnetic responsivity and dispersity. The Co2+ ions in the magnetic nanoparticle shell provide docking site for histidine, and the Fe3O4/Au-ANTA-Co2+ nanoparticles exhibit excellent performance in binding of a His-tagged protein with a binding capacity of 74 mu g/mg. The magnetic nanoparticles show highly selective purification of the His-tagged protein from Escherichia coli lysate. Therefore, the obtained Fe3O4/Au-ANTA-Co2+ nanoparticles exhibited excellent performance in the direct separation of His-tagged protein from cell lysate. Crown Copyright (c) 2013 Published by Elsevier B.V. All rights reserved.